On bottom-up pre-processing techniques for automated default reasoning

  • Thomas Linke
  • Torsten Schaub
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 1638)


In default logic, possible sets of conclusions from a default theory are given in terms of extensions of that theory. Each such extension is generated through a set of defaults rules. In this paper, we are concerned with identifying default rules belonging to all sets of default rules generating different extensions. This is interesting from several perspectives. First, it allows for approximating the set of so-called skeptical conclusions of a default theory, that is, those conclusions belonging to all extensions. Second, it provides a technique usable for pre-processing default theories, because such default rules are applicable without knowing nor altering the extensions of the initial theory. The fact that our technique leaves the resulting conclusions unaffected makes it thus applicable as a universal pre-processing tool to all sorts of computational tasks.


Directed Graph Default Rule Default Theory Initial Theory Default Logic 
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  1. 1.
    C. Froidevaux and J. Mengin. Default logic: A unified view. Computational Intelligence, 10(3):331–369, 1994.CrossRefGoogle Scholar
  2. 2.
    G. Gottlob. Complexity results for nonmonotonic logics. Journal of Logic and Computation, 2(3):397–425, June 1992.zbMATHCrossRefMathSciNetGoogle Scholar
  3. 3.
    F. Lévy. Computing extensions of default theories. In R. Kruse and P. Siegel, editors, Proceedings of the European Conference on Symbolic and Quantitative Approaches for Uncertainty, volume 548 of Lecture Notes in Computer Science, pages 219–226. Springer Verlag, 1991.Google Scholar
  4. 4.
    T. Linke and T. Schaub. An approach to query-answering in reiter’s default logic and the underlying existence of extensions problem. In J. Dix, L. Fariñas del Cerro, and U. Furbach, editors, Logics in Artificial Intelligence, Proceedings of the Sixth European Workshop on Logics in Artificial Intelligence, volume 1489 of Lecture Notes in Artificial Intelligence, pages 233–247. Springer Verlag, 1998.Google Scholar
  5. 5.
    Th. Linke. New foundations for automation of default reasoning. Dissertation, University of Bielefeld, 1999.Google Scholar
  6. 6.
    R. Reiter. A logic for default reasoning. Artificial Intelligence, 13(1-2):81–132, 1980.zbMATHCrossRefMathSciNetGoogle Scholar
  7. 7.
    C. Schwind. A tableaux-based theorem prover for a decidable subset of default logic. In M. Stickel, editor, Proceedings of the Conference on Automated Deduction. Springer Verlag, 1990.Google Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 1999

Authors and Affiliations

  • Thomas Linke
    • 1
  • Torsten Schaub
    • 1
  1. 1.Institut für Informatik, Universität PotsdamPotsdamGermany

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